Zhang D, Nicklas R B
Department of Zoology, Duke University, Durham, North Carolina 27708-1000, USA.
Nature. 1996 Aug 1;382(6590):466-8. doi: 10.1038/382466a0.
Anaphase and cytokinesis are key processes in the segregation of replicated chromosomes to the daughter cells: in anaphase, chromosomes move apart; in cytokinesis, a cleavage furrow forms midway between the separated chromosomes. Some evidence suggests that chromosomes may be involved both in controlling the timing of anaphase onset and in dictating the position of the cleavage furrow. Other evidence indicates that the controlling mechanisms are intrinsic to the spindle and the cell. Here we test these possibilities in grasshopper spermatocytes by observing spindles and cells after removal of chromosomes. We found that both anaphase and cytokinesis occur independently of chromosomes: stage-specific changes occur at an appropriate time and in the correct way, despite the absence of chromosomes. This finding is particularly noteworthy because chromosomes have an important impact on spindle microtubule assembly and the timing of anaphase onset in these cells.
在后期，染色体相互分开；在胞质分裂中，一条分裂沟在分离的染色体之间的中间位置形成。一些证据表明，染色体可能既参与控制后期开始的时间，又决定分裂沟的位置。其他证据则表明，控制机制是纺锤体和细胞所固有的。在这里，我们通过观察去除染色体后的纺锤体和细胞，在蚱蜢精母细胞中测试了这些可能性。我们发现后期和胞质分裂都独立于染色体发生：尽管没有染色体，但特定阶段的变化仍在适当的时间以正确的方式发生。这一发现尤其值得注意，因为染色体对这些细胞中的纺锤体微管组装和后期开始的时间有重要影响。
